Automatic constant tension control with high-speed pick-up



J. G. REEDER AUTOMATIC CONSTANT TENSION CONTROL WITH HIGH-SPEED PICK-UP Jan. 14, 1958 3 Sheets$heet 1 Filed May 11, 1955 JNVENTOR. JACK REEDER, BY: g I

ATTORAE) Jan. 14, 1958 J. G. REEDER A 2,819,512

AUTOMATIC CONSTANT TENSION CONTROL WITH HIGH-SPEED PICK-UP Filed May 11, 1955 3 Sheets-Sheet 2 IN V EN TOR. JACK REBDEIRn M Z. M

A FOX/V5)" Jan. 14, 1958 J. G. REEDER 2,819,512

AUTOMATIC CONSTANT TENSION CONTROL WITH LINE * RECTIFIER- 112 l ,m IF a DRIVING I fffifi 1 2 gas 133 192 79 1? 135 131 188 138133 W7; la! 57% k r 35 84 25 p12: VINO 9 E'IJEC'IWAGNEDC up REY-EA SE ELBcrnaMAaNEr C CLUTCH 1 1a qq INVENTOR.

0140K FEEDER 3 Sheets-Sheet 3 Maw- ATTORNEY United States Patent AUTOMATIC CONSTANT TENSION CONTROL WITH HIGH-SPEED PICK-UP Jack G. Reeder, Columbus, 11111., assignor to The Reliance Electric and Engineering Company, Cleveland, Ohio, a corporation of Ohio Application May 11, 1955, Serial No. 507,614

17 Claims. or. 28-36) The present invention relates to a constant tension control, and more specifically to means for controlling the operation of a rotor or the like, and a delivery means associated therewith, under conditions such that tension in the material passing between the rotor and the delivery means shall be maintained constant throughout the cycle of operation. A primary object of the invention, then, is to provide mechanism establishing control over the transmission of power to a delivery means and a rotor of such character as to accomplish such maintenance of uniform tension.

A further object of the invention is to provide means whereby, as material builds up upon, or is removed from, a storage roll or rotor in an organization of the character above suggested, the ratio between the angular velocities of the delivery means and storage rotor will be progressively modified to compensate for the progressive variation in effective diameter of the storage rotor. A further object of the invention is to provide means whereby, upon completion of a cycle, the starting ratio between such velocities may be readily and quickly reestablished without the necessity of reversing the entire control organization.

A further object of the invention is to provide novel means for regulating the desired tension of a strand or other material being wound on a beam.

A further important object of my invention is to provide an automatic constant tension control device for a beam winding or unwinding machine, said control means being effective to facilitate the accomplishment of a flying splice, whereby the winding onto or unwinding from one beam is terminated and recommenced onto or from another beam without stopping the machine.

A further object of my invention is to provide a constant tension control for a beam winding and unwinding machine which is compact in size and arrangement, safe in operation and dependable in use.

Further objects of the invention will appear as the description proceeds.

One embodiment of the present invention finds its primary utility in the control of a loom beam during the winding of strands thereon; and the invention has been shown, and will be described, in that environment.

To the accomplishment of the above and related objects, my invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific constructions illustrated and described, so long as the scope of the appended claims is not violated.

Fig. l is a plan view of a control constructed in accordance with my invention associated with the beam and delivery roll of such a machine;

Fig. 2 is a fragmentary transverse section taken substantially on the line 2, 2 of Fig. 1;

Fig. 3 is a somewhat diagrammatic ,plan view of a portion of the control mechanism;

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Fig. 4 is an enlarged elevational view of a portion of the control mechanism, taken from the left side of Fig. 1, parts being broken away for clarity of illustration;

Fig. 5 is a wiring diagram embodying one form of my invention; and

Fig. 6 is a wiring diagram embodying another form of my invention.

Referring more particularly to the drawings, it will be seen that I have indicated at 10 a conventional loom beam with which is conventionally associated a delivery roll 11 flanked by idlers 12 and 13. In accordance with conventional practice, strands or other material 14 will be threaded between the idler 12 and the delivery roll -ery of the beam 10. Since materialwill progressively build up on the beam 10 to increase the effective periphery thereof, it will be obvious that, if the delivery roll 11 is driven at constant angular velocity, the angular velocity of the beam 10 must be progressively decreased.

A power source, indicated generally by the reference numeral 15, will preferably comprise an electric motor 16- with which may, if desired, be associated a speed varying transmission unit indicated at 17. For the purposes of disclosing the present invention, it will be as sumed that the unit 17 is operated always at a single setting.

Suitable means, such as a plurality of V-belts 18, transmit power from the motor 16 and unit 17 to a pulley 19 fixed to a jack shaft 20 which is mounted for rotation in suitable bearings parallel with the axes of the delivery roll 11 and the beam 10. A sprocket 21 on the shaft 20 is connected by chains22 to a sprocket23 on a countershaft 24; and power is delivered from said shaft 24 to the delivery roll 11 through a sprocket 25, chains 26, and a sprocket 27 on the shaft 11. It will be clear that the shaft 11 will be driven always at a speed constantly proportional to the speed of the power source 15.

The beam 10 carries a sprocket 28 which is driven, through chains 29, from a sprocket 30 on the output shaft 31 of a reversing, speed-reducing gear unit indicated at 32, said gear unit, in turn, being driven by the output shaft 33 (Fig. 3) of a variable speed transmission 34.

A further sprocket 35 on the shaft 20 is connected by chains 36 to drive the input element 37 of a driving,

electro-magnetic, slipping clutch indicated generally by the reference numeral 38; and the output element 39 of electro-magnetic clutch 38 is drivingly mounted upon the input shaft 40 of the transmission 34, while the input element 37, of course, is free on the shaft 40. Driving clutch 38 will be of the type in which, during maintenance of a given clutch setting, the element 39 will slip and lag behind the element 37 by a constant ratio, so long as the torque demand applied thereto remains constant. As is well known, the torque transmitting capacity of this type of clutch under predetermined load, may be varied by varying the rate of current flow through the clutch. Also, the rate of slip, under any current flow rate setting, will vary in response to variations in the load impressed upon the clutch, in the direction of load variation. Clutches of the character here under consideration are well known in the art and, since the details of clutch structure form no part of 'the present invention, the clutch has been illustrated diagrammatically.

One type of variable speed transmission which may advantageously be used in the practice of my invention is the well known Reeves type which is illustrated somewhat diagrammatically in Fig. 3. Such a transmission comprises a frame in which are journalled the output and input shafts 33 and 40 upon parallel, spaced axes. An expansible V-pulley comprising mating cones 41 rotates with the shaft 40, and a corresponding pulley comprising cones 42 rotates with the shaft 33, an edge active belt 43 providing a driving connection between said pulleys. A lever 44 is operatively connected to one disc of each pulley, through suitable thrust bearings, and a lever 45 is operatively connected to the other disc of each pulley, through thrust bearings, said levers being intermediately pivoted as at 46 and 47 so that, as the projecting ends of the two levers are moved toward each other, the cones 41 will be moved toward each other to increase the effective diameter of the input pulley, while the cones 42 will be moved away from each other to decrease the effective diameter of the output pulley, thereby increasing the speed at which the shaft 33 will be driven in response to a predetermined speed of rotation of the shaft 40. Means is provided for controlling the relative positions of the levers 44 and 45, such means, in the illustrated embodiment of the invention, comprising a fluid motor and means for controlling the same, indicated generally by the reference numeral 48. Such control means may advantageously take the form of the device illustrated and described in the patent to Harry C. Clay, No. 2,306,541, issued December 29, 1942, the cylinder 49 of the motor being secured to the lever 45 and the piston 50 thereof being secured to the lever 44. Valve mechanism for controlling fluid flow to the motor is indicated at 51, and

may include an actuating lever 52.. In the illustrated embodiment 'of the invention, a link 53 is pivotally connected at one end to the actuator 52, and at the other end is pivotally connected to one end of an arm 54. The other end of the arm 54 is adjustably fixed on a shaft 55 which is actuated by mechanism hereinafter to be described.

Flexible shaft 57 is operatively connected through coupling 58 to the driving element 37 of electro-magnetic clutch 38, and shaft 57 thereby rotates at a speed constantly proportional to the speed of the driving element 37. Referring particularly to Fig. 4, it will be seen that flexible shaft 57 leads through an opening in casing 56, thence through a bearing support 59, and is coupled to a differential input shaft 61 by means of coupling 60. Differential shaft 61 is supported for rotation in bearing support 62 and forms one input shaft of differential unit 63. Flexible shaft 65 is driven through coupling 66 at a speed constantly proportional to the speed of shaft 40. Referring again to Fig. 4, it is apparent that flexible shaft 65 is supported by bearing support 67 and coupled to the differential input shaft 69 by means of coupling 68.

Differential shaft 69 is supported for rotation in bearing support 70 and forms a second input shaft of differential unit 63. Differential unit 63 may preferably be generally of the type fully illustrated and described in the patent to William R. Perry, No. 2,168,071, issued August 1, 1939. The arrangement of differential unit 63 is such that, so long as a predetermined ratio between the speeds of shafts 61 and 69 remains constant, differential output shaft 71 will not rotate.

if the rotational speed of flexible shaft 65 should decrease with respect to the rotational speed of flexible shaft 57, the ratio of the relative speeds of shafts 69 and 61 would change in aco'rr'e'spo'ndin'g manner since Shafts 69'and 61 are coupled directly with flexible shafts and 57, respectively. Differential unit 63 would measure this change in relative speeds and drive shaft 71 in a counter-clockwise direction, as viewed from the righthand side of Fig. 4, at a rate proportional to the degree of change in relative speeds. Alternatively, upon an increase in the speed of shaft 69 with respect to that of shaft 61, differential 63 is effective to rotate shaft 71 in a clockwise direction, as viewed from the right-hand side of Fig. 4, at a rate proportional to the magnitude of the change in the ratio of speeds.

It is noted that one of the input shafts of the differential unit referred to in the Perry patent is coupled to the bevelled gear it directly drives by a chain and sprocket arrangement; whereas, the other input shaft is coupled to its respective, directly driven bevelled gear by a meshing gear arrangement. As a result, both of the input shafts of this differential unit are driven in the same direction with consequent rotation of .the respective, directly driven bevelled gears in opposite directions. It will be obvious that both input shafts of the differential unit could be coupled by the same means (whether it be a chain and sprocket arrangement or a gear arrangement) to its respective, directly driven bevelled gear; and the coupling means between one of the flexible shafts and its driving shaft could then be arranged to drive that flexible shaft in the direction of rotation opposite to that of the other. Any of these arrangements may be provided so long as the bevelled gears of the differential unit which are directly driven by the respective input shafts are rotated in opposite directions. Of course, the resultant directions of rotation of the differential output shaft will be determined by the particular arrangement utilized. 7

Pinion 72 is provided in relatively fixed relation on shaft 71, and upon rotation of shaft 71 will rotate gear 73 in the opposite direction. Gear 73 is relatively fixed on the shaft 74 which is rotatably supported on bearing supports 75 and 76. Shaft 74 forms part of the input to electro-magnetic clutch 77, which is preferably of the type whereby when energized, it provides substantially no slip between its input and output elements, and when deenergized, it permits the input and output elements to rotate freely relative to each other. Shaft 78 forms part of the output of clutch 77 and is supported for rotation in bearing support 79. Bevelled gear 80 is provided in relatively fixed relation on shaft 78 and in engagement with gear 81. Referring to Fig. 1 in conjunction with Fig. 4, it will be seen that gear 81 is releasably fixed on shaft 55 by any suitable means such as one or more set screws (not shown).

Rigidly fixed with respect to casing 56, is a bracket 83 having a bearing sleeve 84, within which shaft 55 is journalled. Shaft 55 is relatively fixed longitudinally with respect to sleeve 84 by any suitable releasable means such as stop collars 85 (only one of which is shown in Fig. 1) which are secured to shaft 55 adjacent the opposite ends of sleeve 84 by suitable means such as a set screw 86. A counterweight supported on arm 91 which is adjustably fixed on shaft 55 by means of bracket 92, is provided for a purpose later to be described.

As previously pointed out, the resultant directions of rotation of the differential output shafts are determined by the directions of rotation of the respective differential input shafts and the particular coupling means between each of the differential input shafts and the bevelled gears which they respectively drive. Accordingly, to provide the appropriate resultant directions of rotation of shaft 55, gear 81 may be mounted in either the full line position or the reversed, dotted line position shown in Fig. 1.

In operation, the motor 16 will be energized to drive the assembly, and'a length or lengths of material will be threaded past the delivery roll 11 and to the beam 10, in the manner illustrated in Fig. 2. In the beginning of a cycle, and assuming theroll 11 and the beam to be of equal peripheral dimensions, the roll and the beam will be driven at equal angular velocities. Upon the completion of its first revolution, however, the effective diameter of the beam 10 will begin to increase as the material 14 is laid thereon. Since the two rotors are moving at equal angular velocities, this increase in effective diameter of the beam 10 will tend to increase the tension in the stretch of material extending between the delivery roll and the beam. This increase in tension will have a braking effect on the beam; and that effect will be transmitted, through the chain 29 and the unit 32, to the output shaft 33 of the transmission 34, and thence, through the belt 43, to the input shaft of the transmission. The rate of slip between the parts of the clutch 38 will thus tend to increase, thereby causing the shaft 69 of the differential unit 63 to lag behind the shaft 61 thereof. Differential unit 63 measures that change in the relative rates of rotation of the shafts 61 and 69, whereby shaft 71 is rotated at a proportional speed in a counter-clockwise direction (as viewed from the right-hand side of Fig. 4), to rotate shaft 74 in a clockwise direction with consequent counter-clockwise rotation of gear 81 and shaft as viewed in Fig. 4. Arm 54 will thereby be swung through a corresponding degree to shift lever 52, whereby the valve mechanism 51 will cause piston 50 and cylinder 49 to increase the distance between the ends of levers 44 and 45, whereby the speed ratio between the shafts 40 and 33 of the transmission 34 will be modified to reduce the velocity of the shaft 33. Thereby, the angular velocity of the beam 10 will be progressively reduced, at a rate such as to maintain a constant degree of tension in the stretch of material extending between the delivery roll ll and the beam 10. In the illustrated organization, when the beam 10 has been filled to desired capacity, it is desirable to stop further operation of the control while the beam is dotfed, and it is highly desirable that the control be returned to starting condition promptly, so that there may be no delay in preparing to load a new beam. This prompt return is effected by cooperation between the clutch 77, counterweight and the inter-related control arrangement illustrated in Fig. 5.

Referring particularly to Fig. 5, I have shown a main switch which is connected through leads 96 and 97 to energize the primary side of transformer 98. The secondary side of transformer 98 is connected to rectifier 99 through lead 103 and lead 100, fuse 101 and lead 102. From the other side of rectifier 99, leads 104 and 105 are connected to leads 108 and 109, respectively, which are connected to either side of potentiometer 107. The adjustable contact 110 of potentiometer 107 is connected through lead 111 to an ammeter 112. Electro-magnetic clutch 38 is connected in series relation with the ammeter by means of leads 114 and 115 to one side thereof, and from the other side through leads 116, 117 and 118, back to lead 105. A condenser 119 is connected in shunt relationship across the electro-magnetic clutch 38 by means of leads 120 and 121.

The degree of tension in the reach of material running between the delivery roll and the beam varies directly with the torque transmitting capacity of electro-magnetic clutch 38. Since the torque transmitting capacity of clutch 38 varies directly with the rate of current flow therethrough, theoptimum value of tension in this reach of material may be set by adjusting contact 110 of potentiometer 107 to the corresponding optimum value of current flow. Accordingly, ammeter 112 may be callbrated in units of tension in the reach of material running between the delivery roll and the beam.

"Release electro-magnetic clutch 77 is connected to leads 104 and 105 through leads 123 and 124 on one side of-clutch 77, and through lead 125, fuse 126, lead 127, terminal l28 of selector switch 129, lead and lead 113 611 the other side of clutch 77. Contact 131 or switch 129 is connected through lead 132 to lamp 133 which is connected with terminal 135 of switch 136 through lead 134. Switch 136 is of the normally-closed, plunger type and has a bridge 138 actuated by a plunger 137 to electrically connect and disconnect terminals 135 and 139. Lead 140 connects terminal 139 with lead 123. 1

When the beam 10 has been filled to the desired capacity, the arm of selector switch 129 is moved out of contact with terminal 128 and into contact with terminal 131. Clutch 77 will thereby be deenergized to permit shaft 78 to be readily adjusted rotatably relative to the shaft 74; and lamp 133 is lighted. counterweight 90 will then be free to swing downwardly under the influence of gravity from the position shown in Fig. 4 to which it is moved during winding of the beam 10, causing lever 52 of valve mechanism 5] to return to high speed position. When lever 44 reaches high speed position, it engages and moves plunger 137 of switch 136 to open position, thus deenergizing lamp 133 to indicate that the control is set to resume high speed operation. Motor 16 is stopped, an empty beam is substituted for the full beam and the arm of selector switch 129 is then moved out of contact with terminal 131 and into contact with terminal 128. This energizes release clutch 77 to restablish the substantially non-slip relation between the input and output shafts thereof, and, after reenergization of motor 16, the beam 10 will again be driven with the strand tension, as determined by the current setting of potentiometer 107, maintained substantially constant.

It will be clear that, if the organization were used for unwinding material from a storage reel, shaft 20 would be rotated by power source 15 in the opposite direction from that during winding, and a tendency toward increase in the tension in the stretch of material between the storage roll and the delivery roll would result in the increase of the rate of slip of clutch 38 to produce clockwise rotation of shaft 71. Clockwise rotation of shaft 71 results in clockwise rotation of shaft 55 to thereby shift the ends of levers 44 and 45 toward each other to increase the angular velocity of the shaft 33 as the storage roll empties. Of course, when that roll becomes empty during unwinding operation, clutch 77 will be deenergized and weight 90 will swing downwardly from its position to the left of shaft 55, as viewed in Fig. 4, to rotate shaft 55 in a counterclockwise direction to thereby return transmission 34 to low speed position. Limit switch 137 will be appropriately relocated for unwinding operation of the machine.

t is frequently desirable to make a flying splice, whereby winding of one beam is terminated and that of another is commenced. In Fig. 6, I have shown a modified arrangement whereby this may be quickly and efficiently accomplished.

The parts in Fig. 6 which correspond to those in Fig. 5 are identified by like reference numerals, and the description of these corresponding parts will not be: repeated.

An additional adjustable potentiometer 143 is provided in this embodiment and is connected to leads 108 and 109 in the same relative manner as potentiometer 107, by means of leads 144 and 145. The adjustable contact 146 of potentiometer 143 is connected to lamp 147 which is connected to terminal 149 of a time delay relay 150 through lead 148. Terminal 153 of time delay relay 150 is connected to one side of driving, electro-rnagnetic clutch 38 through leads 151 and 152. Lead 154 connects lead 114 to terminal 155 of relay 150. Terminal 156 of relay 150 is connected to one side of driving, electro-magnetic clutch 38 through leads 157 and 152. Time delay relay 150 is actuated by closing normally-open, push button switch 162, whereby coil mechanism 159 is energized for a predetermined time interval through leads 160 on one side thereof and leads 161 and 163 on the other side.

The operation of the control arrangement shown in Pig. n will now be described to make a flying splice.

Shortly prior to finishing. the winding on a beam, the arm of selector switch 129 is movedinto contact with terminal 131 and out of contact with terminal'128. This deenergizes clutch'77a'nd energizes lamp 133. As in the embodiment shown'in Fig. 5, this permits counterweight 90 to shift'transmission 34 back'to high speed position. As lever 44 reaches high speed position, it will depress plunger 137 of switch 136 to extinguish lamp 133 to indicate that the transmission 34 is now at high speed position. As the transmission 34 begins to move toward high speed position, the slip of clutch38 Will commence to increase to a large degree sinceits normal operating torque setting as effected by' potentiometer 107 will not be sufficiently great to'drive the'beam at highspeed. The speed of motor 16"is substantially reduced to permit the splice to be made. When ready to splice, switch 162'is closed to energize time delay'relay 150, andthe splice is made immediately'thereafter. With'the coil mechanism 159 of relay 150 energized,*bridge '158electrically connects terminals 149 and 153, whereby the reading of ammeter 112 drops to zero and lamp 147 'is lighted. With bridge 158 inengagement with terminals 149and 153, potentiometer 107 is deenergized and potentiometer 143 is energized. Splice potentiometer 143 will have beenadjusted to provide a substantially greater torque capacity of clutch 38' than that effected by potentiometer'107. This greater torque capacity is sufiicient to substantially'eliminate any slipping of clutch 38, and the speed 'of' shaft 40 of the transmission 34 is rapidly brought up to that of the input to clutch 38. The output speed of 'the transmission 34 will now become maximum as determined by the belt and disc positions, and the torque transmitting capacity of clutch 38 as set by potentiometer 143 issuflicient to overcome the inertia of bringing the mass of the finished beam and the empty beam to high speed. Time delay relay 150 is set so that as the beams reach maximum rotational speed, the relay coil is deenergized whereby bridge 158 moves out ofengagement with terminals 149 and 153 and into electrically connecting engagement with terminals 156 and 155. Thus, control of the torque capacity of clutch 38 is returned from potentiometer 143 to potentiometer 107. The arm of selector switch 129 is then moved into contact with terminal128 to reenergize release clutch 77, and the new beam to be filled is under the tension control set by potentiometer 107.

In the operation of both of the embodiments illustrated in Figs. and 6, respectively, to wind material on a beam, it is usually desirable that the tension setting of adjustable contact 110 of potentiometer 107 be increased slightly after moving the arm of switch 129 out of engagement with terminal 128, to compensate for the secondary effect of reduced clutch torque capacity at higher slip values. Then, when the arm of switch 129 is moved back into engagement with terminal 128, adjustable contact 110 is immediately thereafter set back to the original desired wind uptension. When unwinding material from a beam, of course, the tension setting will, alternatively, be initially decreased and subsequently returned to original position at the same respective times.

While my invention has been particularly described and illustrated as a material winding and/or unwinding unit, it will be apparent that its utility is not limited thereto. For example, rotor 11} could be arranged as a material advancing means whereby the unit could be em ployed as a means for advancing material at constant tension between machines which might operate upon the advancing material.

I claim as my invention:

1. In a device of the class described, a delivery means and a rotor, said delivery means being driven at a velocity constantly proportional to the lineal velocity of a reach of material running between said delivery means and said rotor, and means for controlling tension in said reach of material, said last mentioned means comprising means for driving said rotor at variable speeds including a power source, a speed varying transmission including a driving shaftja driven shaft, means providing a driving, connection between said shaftsyand an element shiftable oppositely to vary oppositely the transmission ratio between saidshafts, means connecting said transmission driven shaft to drive said rotor, means connecting said powersource to drive said transmission driving shaft, said last named means including an electrically-energized clutch-whose torque transmitting capacity is variable in accordance with variations in'the rate of current flow through the clutch, a differential mechanism including two input'shafts and an output shaft which rotates only upon departure from a predetermined ratio between the speeds of said differential mechanism input shafts, means driving one of said input shafts at a speed proportional to the speed of said transmission driving shaft, and means driving the other of said input. shafts at a speed proportional to the speed of said delivery means, means operatively connecting said difierential mechanism output shaft to shift said shiftable element, and means for adjusting the torque transmitting capacity of said clutch including meansfor varying the rate of current flow through said clutch to thereby adjust the tension on the reach of material running between said delivery means and said rotor.

2. The device of claim 1 wherein said means for varying the rate of current flow through said clutch comprises a potentiometer having its variable contact connected electrically in series relation with said clutch.

3. In a device of the class described, a delivery means and a rotor, said delivery means being driven at a velocity constantly proportional to the lineal velocity of a reach of material running between said delivery means and said rotor, and means for controlling tension in said reach of material, said last-mentioned means comprising means for driving said rotor at variable speeds including a power source, a speed varying transmission including a driving shaft, a driven shaft, means providing a driving connection between said shafts, and an element shiftable oppositely to vary oppositely the transmission ratio between said shafts, means connecting said transmission driven shaft to drive said rotor, means connecting said power source to drive said transmission driving shaft, said last-named means including an electrically-energized clutch whose torque transmitting capacity is variable in accordance with variations in the rate of current flow through the clutch, a differential mechanism including two input shafts and an output shaft which rotates only upon departure from a predetermined ratio between the speeds of said differential mechanism input shafts, means driving one of said input shafts at a speed proportional to the speed of said transmission driving shaft, means driving the other of said input shafts at a speed proportional to the speed of said delivery means, means operatively connecting said differential mechanism output shaft to shift said shiftable element, and means for adjusting the torque transmitting capacity of said clutch in-.v

means for operatively connecting said shiftable element and said differential, mechanism output shaft including a second electrically energized clutch, said second clutch being electrically connected in parallel relation with said first mentioned clutch, and switch means electrically connected in series relation with said second clutch to deenergize said second clutch while effecting comparatively,

rapid speed changes of said transmission output shaft.

4. The device of claim 3 including a limit switch means.-

and an indicating means electrically connected in series relation with each other and in parallel relation with said 3' second clutch such that when said second clutch is de-:

energized by said first mentioned switch means, saidindicating means is energized and remains energized during the interval before said second 'clucth is properly reenergized.

5. The .device of claim 4 wherein said limit switch means comprises a normally closed switch which is opened byengagement of the actuating means of the limit switch with said shiftable element.

6. Ina device ofthe class described, a delivery means and a rotor, said delivery means being driven at a velocityconstantly proportional to the lineal velocity of a reach of material running between said delivery means and said rotor, and means for controlling tension in said reach .of material, said last-mentioned. means comprising meansforidriving said rotor at variable speeds including a power source, a speed varyingtransmission including atdrivingshafna driven shaft, means'providing a driving connection between said shafts, and anselementshiftable oppositely to vary oppositely the transmission ratio between .said shafts, means connectingsaid transmission driven shaft todrive said rotor, .meansconnecting said powersource to drive said transmission'driving shaft, said last-named means including an electrically-energized clutch whose. torque transmitting capacityis variable in accordance with variations in the rate of current flow through the clutch, a differential mechanism including twoinput shafts and an output shaft which rotates only upon departure from a predetermined ratio between the speeds of said differential mechanism input shafts, means driving one of said input shafts at a speed proportional to the speed of said transmission driving shaft, and means driving the other of said input shafts at a speed proportional to the speed of said delivery means, means including a second electrically-energized clutch operatively connecting said dilferential mechanism output shaft to shift said shiftable element, said second clutch being electrical- 1y connected in parallel relation with said first-mentioned clutch, switch means electrically connected in series relation with said second clutch to deenergize said second clutch while effecting comparatively rapid speed changes of said transmission output shaft, and means for adjusting the torque transmitting capacity of said clutch including means for varying the rate of current flow through said clutch thereby to adjust the tension on the reach of material running between said delivery means and said rotor.

7. The device of claim 6 including a limit switch means and an indicating means electrically connected in series relation with each other and in parallel relation with said second clutch such that when said second clutch is deenergized by said first mentioned switch means, said indicating means is energized and remains energized during the interval before said second clutch is properly re-energized.

8. The device of claim 7 wherein said limit switch means comprises a normally closed switch which is opened by engagement of the actuating means of the limit switch with said shiftable element.

9. In a device of the class described, a delivery means and a rotor, said delivery means being driven at a velocity constantly proportional to the lineal velocity of a reach of material running between said delivery means and said rotor, and means for controlling tension in said reach of material, said last-mentioned means comprising means for driving said rotor at variable speeds including a power source, a speed varying transmission including a driving shaft, a driven shaft, means providing a driving connection between said shafts, and an element shiftable oppositely to vary oppositely the transmission ratio between said shafts, means connecting said transmission driven shaft to drive said rotor, means connecting said power source to drive said transmission driving shaft, said last-named means including an electrically-energized clutch whose torque transmitting capacity is variable in accordance with variations in the rate of current flow 10 through the clutch, a differential mechanism including two input shafts and an output shaft which rotates only upon departure from a predetermined ratio between the speeds of said differential mechanism input shafts, means driving one of said input shafts at a speed proportional tothe speed of said transmission driving shaft, means driving the other of. said input shafts at a speed proportional to thespeed of=said delivery means, means operatively connecting said differential mechanism output shaft to shift said shiftable element, means for adjusting the torque transmitting capacity of .said clutch including .meansfor varyingtthe rate of current flow through said clutch thereby to adjust the tension on the reach of material running between said delivery means and said rotor, said means for varying :the rate of current flow through saidsclutchincluding twomeans, each of whichisadjustable to vary the rate of current flowthrough said clutch,-and"controlmeans havingmeans shiftable oppositely to connect said adjustable means alternatively in domination overfsaidiolutch.

1-0. The device iof claim 9 wherein said means for ope'ratively connecting saidshiftable element and said differentialmechanisrn output shaft includes a secondelectrically energized ol utch,-said second clutch being electrically connected in;parallel relation with said first mentionedclutch and switch-means electrically connected in-series irelation' with said second clutch to deenergize saidsecond clutch while effecting comparatively rapid.

speed changes of said transmission output shaft.

11. The device of claim 10 wherein said control means comprises a time delay relay.

12. The device of claim 11 including a limit switch means and an indicating means electrically connected in series relation with each other and in parallel relation with said second clutch such that when said second clutch is deenergized by said first mentioned switch means, said indicating means is energized and remains energized during the interval before said second clutch is properly re-energized.

13. The device of claim 12 wherein said limit switch means comprises a normally closed switch which is opened by engagement of the actuating means of the limit switch with said shiftable element.

14. In a device of the class described, a delivery means and a rotor, said delivery means being driven at a velocity constantly proportional to the lineal velocity of a reach of material running between said delivery means and said rotor, and means for controlling tension in said reach of material, said last-mentioned means comprising means for driving said rotor at variable speeds including a power source, a speed varying transmission including a driving shaft, a driven shaft, means providing a driving connection between said shafts, and an element shiftable oppositely to vary oppositely the transmission ratio between said shafts, means connecting said transmission driven shaft to drive said rotor, means connecting said power source to drive said transmission driving shaft, said last-named means including an electrically-energized clutch whose torque transmitting capacity is variable in accordance with variations in the rate of current flow through the clutch, a differential mechanism including two input shafts and an output shaft which rotates only upon departure from a predetermined ratio between the speeds of said differential mechanism input shafts, means driving one of said input shafts at a speed proportional to the speed of said transmission driving shaft, means driving the other of said input shafts at a speed proportional to the speed of said delivery means, means operatively connecting said differential mechanism output shaft to shift said shiftable element, means for adjusting the torque transmitting capacity of said clutch including means for varying the rate of current flow through said clutch thereby to adjust the tension on the reach of material running between said delivery means and said rotor, said means for varying the rate of current flow through said clutch including a first potentiometer and a second potentiometer, the variable contact of each of said potentiometers being electrically connected in series relation with said clutch, and control means eifective, when actuated, to first deenergize said first potentiometer and energize said second potentiometer for a predetermined interval, and then re-energize said first potentiometer and deenergize said second potentiometer.

15. The device of claim 14 wherein said means for operatively connecting said shiftable element and said differential mechanism output shaft includes a second electrically energized clutch, said second clutch being electrically connected in parallel relation with said first mentioned clutch, and switch means electrically connected to deenergize said second clutch after deenergization and before reenergization of said first potentiometer.

16. The device of claim 15 wherein said control means comprises a time delay relay.

17. In a device of the class described, a delivery means and a rotor, said delivery means being driven at a velocity constantly proportional to the lineal velocity of a reach of material running between said delivery means and said rotor, and means for controlling tension in said reach of material, said last mentioned means comprising means for driving said rotor at variable speeds including a power source, a speed varying transmission including a driving shaft, a driven shaft, means providing a driving connection between said shafts, and an element shiftable oppositely to vary oppositely the transmission ratio between said shafts, means connecting said transmission driven shaft to drive said rotor, an electrically-energized clutch having a driving shaft and a driven shaft, the torque transmitting capacity of said clutch being variable in accordance with variations in the rate of current flow through the clutch, means connecting said power source to drive said clutch driving shaft, means operatively connecting said clutch driven shaft to drive said transmission driving shaft at a speed proportional to said clutch driven shaft, a differential mechanism including two input shafts and an output shaft which rotates only upon departure from a predetermined ratio between the speeds of said differential mechanism input shafts, means driving one of said differential mechanism input shafts at a speed proportional to said clutch driven shaft, and means driving the other of said differential mechanism input shafts at a speed proportional to said clutch driving shaft, means operatively connecting said differential mechanism outputshaftto shift said shiftable element, and means for adjusting the torque transmitting capacity of said clutch including means for varying the rate of current flow through said clutch to thereby adjust'the tension on the reach of material running between said delivery means and said rotor.

References Cited in the file of this patent UNITED STATES PATENTS 2,608,741 Reeves Sept. 2, 1952 

